I listened with considerable interest to a BBC radio debate today relating to a published report claiming that 1.8million UK residents are "diagnosed" as suffering from CKD. http://www.bbc.co.uk/iplayer/episode/b01lt2vn/Inside_Health_Overdiagnosis/
On the program, Dr Donal O'Donaghue (Salford, UK) was defending such a growing vue calling for more detection and prevention as well as resources to manage this growing healthcare challenge. In effect, he was championing the prevaling, fashionable, view of rising CKD prevalence, the value of early detection and prevention and so many more often repeated but unsubstantiated and unproven assertions.
Dr Chritopher Winearls (Oxford, UK) was challenging this dogmatic vue, pointing out the inaccuracies of such prevalence statements, issues with detection and prevention programs as well as the grave concern over medicalisation of age-related decline in kidney function.
As often is the case, when the advocate of rising CKD are in trouble with their argument, they fall back on the "But CKD is a major CVD risk factor, so we need to detect it and prevent it...." argumement. One by the way totally refuted by most cardiologists and many nephrologists such as myself for the following reasons:
1. CKD is a MANIFESTATION of underlying CVD not its primary CAUSE, as I stated on many occassions on OLA; I even called the condition Cardio-Kidney-damage (C-K-D) in a 2010 Publication in KI.
2. In support of such argument is that subclinical CVD often precedes incident CKD in older individuals and accelerates its decline.
Here I refer to a number of publications showing that baseline atherosclerosis deteceted by raised carotid intima-media thickness predicts incident CKD (Choncol et al. http://www.ncbi.nlm.nih.gov/pubmed/18388124) and that those with subclinical cerebrovascular disease also have accelerated CKD decline within the community. http://www.ncbi.nlm.nih.gov/pubmed/20537454
This month in cJASN an article by Park et al. report on an observation from the Multi-Ethnic Study of Atherosclerosis (MESA) were they followed up 3,866 individuals (mean age 60) in the USA for approximately 5 years. They reported that those who go on to develop CKD have underlying CVD defined as subclinical cardiac hypertrophy detected by MRI. The presence of ventricular concentricity/hypertrophy increased risk of CKD develkopment (eGFR<60) but also that of increased risk of faster eGFR decline. This was independent of confounders such as hypertension and diabetes.
This supports once more the notion that older individuals with CKD have underlying CVD rather than the other way round. Consequently, it is not surprising that patients with CKD, a marker of underlying diffuse vascular pathology, have a worse CV outcome.
3. And perhaps more importantly, it is most likely that the underlying subclinical CVD that precede CKD may be the reflection of subclinical or underdiagnosed hypertension. In this week's Lancet a series of article stress the fact that systemic hypertension is both underdiagnosed and undertreated in developed as well as developing countries. The fact that casual/office blood pressure measurement is most unreliable and does not reflect 24h ambulatory blood pressure measurements or nocturnal hypertension known to be more closely associated with CVD.
It is likely that it is hypertension and the associated CVD that lead to CKD not the other way round.
30-40% of the population sufferes from hypertension.
Prevention and early Detection of Hypertension: YES, this should be the nephrologists' message!
Ultimately, CKD would, undoubtedly through hypertension and other uremia related factors, accelerate the progression of CVD; a vicious cycle described by Sir Richard Bright almost two centuries ago...!!!!
One of my favourite non-nephrology medical writers has to be Des Spence whose blog (http://bad4umedicine.blogspot.co.uk/) is rapidly becoming a must read. After previously dismissing chronic kidney disease as ' a failed experiment, a mockery of evidence-based medicine', Spence turns his attention to the $3 billion fine imposed Glaxo Smith Kline over amongst other things suppression of data concerning the cardiovascular risks of rosiglitazone. Spence points out that despite its' faults, pharma is essentially an industry ' doing untold good' and that its far too easy to blame pharma - he argues the real problem is a 'global medical culture' that encourages naivety and deference rather than respect and scepticism. In particular he is scathing about expert panels who he describes as 'educational mercenaries'.
Now whilst I don't agree all of his arguments reading his article reminded me of the time I visited a pharma-sponsored symposium at the WCN/ISN in Milan a few years ago. At that symposium Dr Geoffrey Block from Denver gave an impassioned talk on the evils of phosphorus in CKD. Phosphorus increased vascular calcification in CKD and the only way to reduce phosphorus was to use more dialysis and/or more phosphate binders (presumably the rather expensive non-calcium binders). What i remember more than anything was the call for phosphorus to be recognised as a cardiac toxin in CKD patients with a plea for food labelling - so that high phosphorus foods would receive some kind 'health warning' analogus to say high salt warnings that appear on much food packaging now. There was not much discussion of the negative DCOR study (a huge study showing sevelamer had no impact on mortality in dialysis patients) but instead a focus on how we probably needed to reduce phosphorus in the predialysis population.
So hows that all going? Well a recent publication in JASN online by Block suggests that the ' calcium bad, sevelamer/lanthanum good' narrative that has been pushed very hard by pharma (with I am afraid the collusion of some 'experts' in the CKD-MBD field), does not as yet stand up to any critical scrutiny...In this study 148 patients with estimated GFR=20–45 ml/min per 1.73 m2 were assigned to calcium acetate, lanthanum carbonate, sevelamer carbonate, or placebo. The primary endpoint was change in mean serum phosphorus from baseline whilst secondary endpoints looked at effects on FGF23, vascular calcification and bone mineral density. No surprise that the study met its primary endpoint - yes phosphate binders reduce serum phosphorus more effectively than placebo! As expected iPTH levels were significantly higher in the placebo group compared to the binder group at 9 months though interestingly FGF-23 levels were unchanged. In a subset of 90 patients (60 with binders and 26 placebo) imaging was performed which revealed some interesting results. Patients on phosphate binders had a small but significant increase in bone mineral density but a also a significant increase in progression of coronary artery calcification! The authors rather optimistically state that 'The apparent adverse effects on vascular calcification and salutary effects on BMD were most pronounced among patients randomized to calcium acetate' yet no statistics are provided - probably because only 20 patients on binders had an increase in calcification over 9 months and so any meaningful analysis of these 20 patients on three different binders was not possible!!
So what do I make of it all?
i) There is absolutely no RCT evidence to show that non-calcium binders are superior to calcium-based binders in the dialysis population on key patient centred outcomes such as death
ii) Whilst many have argued that the thresholds for serum phosphorus in the pre-dialysis population should be lowered, there is as yet no evidence to support this. In fact what this study shows is that further lowering of serum phosphorus with binders in predialysis patients with CKD may actually not be safe. Until an RCT comes out the honest answer is that we just dont know what to do..
iii) As nephrologists we can spend money in all sorts of ways... prescribing expensive drugs, employing more nursing staff, more dieticians, more counsellors, more dialysis... For those of us who work in an environment where money is an issue, if we are going to prescribe expensive drugs (in the UK the non-calcium binders are around ten times as expensive as calcium binders) we need to have solid data to show that these drugs have a significant impact on outcomes that matter to patients such as death, fractures, hospitalisations, quality of life.. I am afraid I see no robust data for the non-calcium binders
iv) It is entirely appropriate for pharmaceutical companies to push agendas that are going to maximise sales of their products. As Des Spence says we need experts who have a sense of scepticism and are not simply 'educational mercenaries'. But more than that as individual nephrologists we have a duty not to blindly accept expert opinion in the absence of data....
1. Effects of Phosphate Binders in Moderate CKD. Geoffrey A. Block, David C. Wheeler, Martha S. Persky, Bryan Kestenbaum, Markus Ketteler, David M. Spiegel, Matthew A. Allison, John Asplin, Gerard Smits, Andrew N. Hoofnagle, Laura Kooienga, Ravi Thadhani, Michael Mannstadt, Myles Wolf and Glenn M. Chertow. JASN online July 2012
Using measured GFR (by iohexol plasma clearance) the GFR study investigators released new results on progression of type 2 diabetes associated nephropathy, showing that blood pressure and metabolic control are the most important factors associated with slow long-term GFR decline. They based the analyses in data from 2 previously published trials using ACE inhibitors and calcium channel blockers (BENEDICT-B and DEMAND). The most important finding was that controlling hyperfiltration in the first 6 months of treatment was associated with slower progression. That control was most impressive in patients with improved blood pressure and metabolic control, despite of using or not ACE inhibitors. That information is important once, so far, ACEi are ascribed as the first line drugs for the treatment of hypertension in those patients. In fact, manidipine and delapril association showed beneficial effects on cardiovascular disease, retinopathy, and neuropathy and stabilized insulin sensitivity, but had no effect on GFR decline (DEMAND trial). Despite of efforts to find particular drug interventions on complex diseases, as type 2 DM, we should rely on the old and solid concept that blood pressure and glycemic control are the most important, no matter how it is achieved.
Ruggenenti P, Porrini EL, Gaspari F, Motterlini N, Cannata A, Carrara F, Cella C, Ferrari S, Stucchi N, Parvanova A, Iliev I, Dodesini AR, Trevisan R, Bossi A, Zaletel J, Remuzzi G; for the GFR Study Investigators (see Study Organization). Glomerular Hyperfiltration and Renal Disease Progression in Type 2 Diabetes. Diabetes Care. 2012 Jul 6. [Epub ahead of print]
Ruggenenti P, Fassi A, Ilieva AP, Iliev IP, Chiurchiu C, Rubis N, Gherardi G, Ene-Iordache B, Gaspari F, Perna A, Cravedi P, Bossi A, Trevisan R, Motterlini N, Remuzzi G; BENEDICT-B Study Investigators. Effects of verapamil added-on trandolapril therapy in hypertensive type 2 diabetes patients with microalbuminuria: the BENEDICT-B randomized trial. J Hypertens. 2011 Feb;29(2):207-16.
Ruggenenti P, Lauria G, Iliev IP, Fassi A, Ilieva AP, Rota S, Chiurchiu C, Barlovic DP, Sghirlanzoni A, Lombardi R, Penza P, Cavaletti G, Piatti ML, Frigeni B, Filipponi M, Rubis N, Noris G, Motterlini N, Ene-Iordache B, Gaspari F, Perna A, Zaletel J, Bossi A, Dodesini AR, Trevisan R, Remuzzi G; DEMAND Study Investigators. Effects of manidipine and delapril in hypertensive patients with type 2 diabetes mellitus: the delapril and manidipine for nephroprotection in diabetes (DEMAND) randomized clinical trial. Hypertension. 2011 Nov;58(5):776-83. Epub 2011 Sep 19.
Anyone who read my ASN blog will know that Remuzzi's group from Bergamo presented what appeared to be very positive data on the role of Rituximab in idiopathic membranous glomerulonephritis (IMN) at the ASN in 2011. Well the data has finally been published and serves as a salutory reminder to me that one always needs to see the final paper before being able to assess the impact on ones' practice. Remuzzi presents data on a 100 consecutive patient with IMN treated with Rituximab. The median duration of persistent proteinuria prior to rituximab therapy was over 2 years and follow up data was available for a median of 29 months. 27% achieved complete remission whilst 38% achieved partial remission (defined as less than 3g/24 hours and a 50% reduction in proteinuria from baseline). The authors suggest that 'Rituximab might be considered as first line therapy' for IMN. Does the data justify such a statement? Almost certainly not and its worth considering the following:
i) Given the very variable remission and progression rate with IMN, any therapeutic data without a control group is of limited value (some would say meaningless...). IMN runs a highly variable course with a high rate of spontaneous remission that occur can occur even quite late after presentation. This was observed not only by the GLOSEN group in Spain but by Remuzzi himself who when publishing in the NEJM on presumably another cohort of of 100 IMN patients found that 65% of patients went into complete or partial remission after 5 years of observation prompting him to note that 'Most untreated patients with idiopathic membranous nephropathy maintain renal function for prolonged periods and are likely to have spontaneous remission'......
ii) Following on from the above its worth noting that the serum creatinine and 24 hour urinary protein excretion was lower and the serum albumin was higher at baseline in the complete remission group versus the no remission group.. so the question arises did the complete remission group have milder disease that would just get better anyway. Of course unless you have a control you just dont know!
ii) Only 32 patients had recieved prior immunosuppression and of these only 24 had prior steroids in combination with an alkylating agent - this is currently the KDIGO recommended first line therapy as as Gerald Appel points out in an accompanying editorial, given the fact that we have placebo controlled RCTs with both CNIs and alkylating agents, but not with Rituximab, why should we use Rituximab as first line therapy?
iii) the authors cite safety concerns of cyclophosphamide although the cumulative dose of cyclophosphamide used in IMN is relatively low and the safety of Rituximab in auto-immune disease (in terms of side effects such as progressive multifocal leucoencepholopathy) maybe different than in those with lymphoma.
iv) Rituximab is expensive. The authors state that as they only use one dose (375mg/m2) costs are reduced though its worth noting that 18 patients with rituximab relapsed and required a second dose. The use of phospholipase A2 receptor antibodies as a guide to dosing schedule may make more sense.
Taking this work together with Fernando Fervenza's data from the Mayo Rituximab is probably better than placebo in IMN. Its expensive and until there is an RCT comparuing it with an alkylating agent or a CNI I would only use in those patients with progressive IMN who are refractory to (or have contraindications to) alkylating agents therapy and/or calcinuerin inhibitors.
1.Rituximab in Idiopathic Membranous Nephropathy. Piero Ruggenenti, Paolo Cravedi, Antonietta Chianca, Annalisa Perna, Barbara Ruggiero, Flavio Gaspari, Alessandro Rambaldi, Maddalena Marasà, and Giuseppe Remuzzi. J Am Soc Nephrol published 19 July 2012, 10.1681/ASN.2012020181
2. Prognosis of untreated patients with idiopathic membranous nephropathy. Schieppati A, Mosconi L, Perna A, Mecca G, Bertani T, Garattini S, Remuzzi G, N Engl J Med. 1993 Jul 8;329(2):85-9.
3. Spontaneous remission of nephrotic syndrome in membranous nephropathy with chronic renal impairment. Nephrol Dial Transplant 2012 Jan;27(1):231-4. Epub 2011 May 30. Polanco N, Gutiérrez E, Rivera F, Castellanos I, Baltar J, Lorenzo D, Praga M, Grupo de Estudio de las Enfermedades Glomerulares de la Sociedad Española de Nefrología (GLOSEN)
4. Rituximab therapy in idiopathic membranous nephropathy: a 2-year study. Fervenza FC, Abraham RS, Erickson SB, Irazabal MV, Eirin A, Specks U, Nachman PH, Bergstralh EJ, Leung N, Cosio FG, Hogan MC, Dillon JJ, Hickson LJ, Li X, Cattran DC; Mayo Nephrology Collaborative Group. . 2010 Dec;5(12):2188-98.
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This study by Giovanni Stallone1,etal published early online -NDT Advance Access published July 10, 2012 added to the 3 previously published studies about the role of Rapamycin for the treatment of ADPKD.
In this prospective, open-label randomized clinical trial, 55 ADPKD patients followed in the outpatient clinic of the two participating centres (University of Foggia and Bari, Italy) were enrolled between November 2007 and November 2008. The duration of the planned follow-up was
The inclusion criteria were clinical, genetic and ultrasonographic diagnosis of type I ADPKD, age between 18 and 65 years and an estimated glomerular filtration rate (eGFR) between 40 and 80 mL/min/1.73 m2, evaluated by the abbreviated Modification of Diet in Renal Disease (MDRD) formula
The primary objectives were to assess whether rapamycin may reduce the progressive increase in single cyst and total kidney volume in type I ADPKD and the decline in renal function and to identify the optimal rapamycin dose to achieve the beneficial results without incurring inmajor side effects.
After a screening assessment, all patients entered a run-in phase of 2 months in which eGFR and 24 h proteinuria were evaluated every 2 weeks. At the beginning of this period, in patients already treated with angiotensin-converting enzyme inhibitors (ACE-I) and angiotensin II receptor blockers (ARBs), these drugs were withdrawn for at least 4 weeks before performing the laboratory tests.
At the end of the run-in phase, all eligible patients were randomly assigned to ramipril alone (Group A) or ramipril plus high-dose rapamycin (Group or ramipril plus low-dose rapamycin (Group C). In Group B, rapamycin administration was given with a loading dose of 3 mg. The maintenance dose was 1 mg/day aiming at a blood trough level between 6 and 8 ng/mL. In Group C, the patients did not receive a
loading dose and the maintenance dose of rapamycin was 1 mg/day to reach a blood trough level between 2 and 4 ng/mL.
Magnetic resonance imaging technique .All patients recruited for our study underwent a standardized magnetic resonance imaging (MRI) examination at the baseline (T = 0) and after 24 months of initiation of drug therapy (T = 24) with the same MRI scanner.
DNA isolation and linkage analysis. Genomic DNA was derived from whole blood using Purelink Genomic DNA Mini kit (Invitrogen), according to the manufacturer’s protocol.
Epidermal growth factor urinary concentration:
was evaluated by ELISA and the results were normalized to urine creatinine excretion.
The mean rapamycin trough levels were 6.4 ± 0.3 ng/mL for Group B and 3.2 ± 0.4 ng/mL for Group C. The differences between the two groups were statistically significant at each time point for Group C.
In all three groups of patients, They observed an increased total kidney volume. Specifically,
in Groups A and B, there was a statistically significant increase in kidney volume after 24 months of treatment (P = 0.003 and 0.02, respectively), while in Group C, the increase failed to reach the statistical significance However, they did not observe any significant difference in change of kidney volume among the three study groups at the end of the observational period.
On the contrary, the cyst volume was increased in Group A patients after 24 months of treatment (P < 0.0001 versus basal), whereas it was significantly reduced in Group B (P < 0.0001 versus basal) and Group C (P <0.0001 versus basal) Also, in the case of single cyst volume, they did not observe any
significant difference among the three study groups at the end of the observational period.
Renal function analysis. They observed a decline in estimated creatinine clearance in Group A patients (P = 0.01, T24 versus T0),whereas in Groups B and C after 24 months, they observed
a slight increase in GFR, although the differences did not reach statistical significance .
The changes in the estimated creatinine clearance in the three groups at
the end were not significantly different.
EGF urine excretion. an increased EGF urinary excretion in Group A patients (P =0.001 versus T0) was observed, whereas the treatment groups were characterized by a significant reduction after 24 months
(Group B: P = 0.0001 versus T0; Group C: P = 0.0001 versus T0)
The results of this pilot study suggest that rapamycin treatment at a dose effectively inhibiting p70S6 kinase in circulating PBMCs does not significantly slow down cyst growth and renal function decline featuring the natural history of ADPKD